Question

find the value of it by simplification​

Answer 1

Answer:

3/4

Step-by-step explanation:

Let cos

2

76+cos

2

16−cos76cos16=I

I=cos

2

(60+16)+cos

2

16−cos(60+16)cos16

Using cos(A+B)=cosAcosB−sinAsinB

I=(cos60cos16−sin60sin16)

2

+cos

2

16−(cos60cos16−sin60sin16)cos16

=

4

cos

2

16

+

4

3sin

2

16

−

2

3

cos16sin16

+cos

2

16−

2

cos

2

16

+

2

3

cos16sin16

=

4

3cos

2

16

+

4

3sin

2

16

=

4

3